Fig 1.
Effect of different moisturizing pretreatments on (A) cleanliness scores and (B)surface microbial residues (ATP RLU values) of surgical high-speed long fissure burs (mean ± SD).
(T1, T2, T3, and T4 indicate the cycle of reuse. Statistical significance: * P < 0.05; ** P < 0.01; ***P < 0.001; ns: P > 0.05 (not significant).
Fig 2.
Effects of different moisturizing pretreatments on (A) cleanliness scores and (B) surface microbial residues (ATP RLU values) of slow-speed round burs (mean ± SD).
(T1, T2, T3, and T4 indicate the cycle of reuse. Statistical significance: * P < 0.05; ns, P > 0.05 (not significant).
Fig 3.
Effect of different moisturizing pretreatments on (A) cleanliness scores and (B) surface microbial residues (ATP RLU values) of Ni-Ti root canal instruments (mean ± SD).
(T1, T2, T3, and T4 indicate the cycle of reuse. Statistical significance: * P < 0.05; ** P < 0.01; ns, P > 0.05 (not significant.).
Fig 4.
SEM micrographs of instruments pretreated with water, showing microbial attachment and structural wear after four reuse cycles.
Representative images from: (A-C) Surgical high-speed long fissure bur (WF group); (D-F) Slow-speed round bur (WR group); and (G-I) Ni-Ti root canal instrument (W-NiTi group). (A) Fissure bur at 200 × magnification, indicating substantial accumulation of debris. (B) Fissure bur at 2000x magnification, showing structural damage and debris. (C) Fissure bur at 10000 × magnification, detail of an area filled with debris. (D) Round bur at 200 × magnification, indicating the presence of debris. (E) Round bur at 2000 × magnification, showing structural damage with partial areas filled with debris. (F) Round bur at 10000 × magnification, detail of damage and debris. (G) Ni-Ti instrument at 200 × magnification, showing relatively little debris on the main shaft. (H, I) Active tip of the Ni-Ti instrument at 2000× and 10000 × magnification, respectively, showing obvious structural damage.
Fig 5.
SEM micrographs of instruments pretreated with multi-enzyme cleaner, showing microbial attachment and structural wear after four reuse cycles.
Representative images from: (A-C) Surgical high-speed long fissure bur (EF group); (D-F) Slow-speed round bur (ER group); and (G-I) Ni-Ti root canal instrument (E-NiTi group). (A) Fissure bur surface at 200 × magnification, with some adhered debris. (B) Fissure bur at 2000 × magnification, structural damage is present. (C) Fissure bur at 10000 × magnification, detail of structural damage. (D) Round bur at 200 × magnification, no obvious gross debris. (E) Round bur at 2000 × magnification, showing structural damage and some debris. (F) Round bur at 10000 × magnification, detail of damage and debris. (G, H, I) Ni-Ti instrument at 200 × , 2000 × , and 10000 × magnification, respectively, showing relatively little debris and minor structural damage.
Fig 6.
SEM micrographs of instruments pretreated with professional moisturizer, showing microbial attachment and structural wear after four reuse cycles.
Representative images from: (A-C) Surgical high-speed long fissure bur (MF group); (D-F) Slow-speed round bur (MR group); and (G-I) Ni-Ti root canal instrument (M-NiTi group). (A) Fissure bur surface at 200 × magnification, with little adhered debris but some structural damage visible. (B) Fissure bur at 2000 × magnification, detail of structural damage. (C) Fissure bur at 10000 × magnification, further detail of obvious structural damage. (D) Round bur at 200 × magnification, no obvious gross damage. (E) Round bur at 2000 × magnification, showing some structural damage and minimal debris. (F) Round bur at 10000 × magnification, detail of structural damage. (G, H, I) Ni-Ti instrument at 200 × , 2000 × , and 10000 × magnification, respectively, showing very little debris and minimal structural damage.
Fig 7.
EDS analysis of adhered debris on a representative surgical high-speed long fissure bur from the WF group (water pretreatment) after four reuse cycles.
The main image shows an SEM micrograph with numbered areas (1-4) selected for EDS. Accompanying graphs/spectra display the elemental composition for each selected area. (Key elements: Si, Silicon; W, tungsten; Al, aluminum; Au, gold (likely from sputter coating for SEM); C, carbon; Ca, calcium; Co, cobalt; Fe, iron; Mg, magnesium; Na, sodium; Ni, nickel; O, oxygen; P, phosphorus). High levels of Ca and P in debris areas (e.g., areas 1, 3, 4) suggest biological residues.
Fig 8.
EDS analysis of the surface of a representative slow-speed round bur from the MF group (professional moisturizer pretreatment) after four reuse cycles.
The main image shows an SEM micrograph with numbered areas (1-4) selected for EDS. Accompanying graphs/spectra display the elemental composition for each selected area. (Key elements: Si, Silicon; W, tungsten; Al, aluminum; Au, gold (likely from sputter coating for SEM); C, carbon; Ca, calcium; Co, cobalt; Fe, iron; Mg, magnesium; Na, sodium; Ni, nickel; O, oxygen; P, phosphorus). Analysis indicates the primary composition of tungsten (W) with minimal biological indicators in cleaner areas.
Fig 9.
EDS analysis of the surface of a representative Ni-Ti root canal instrument from the W-NiTi group (water pretreatment) after four reuse cycles.
The main image shows an SEM micrograph with numbered areas (1-4) selected for EDS. Accompanying graphs/spectra display the elemental composition for each selected area. (Key elements: Si, Silicon; W, tungsten; Al, aluminum; Au, gold (likely from sputter coating for SEM); C, carbon; Ca, calcium; Co, cobalt; Fe, iron; Mg, magnesium; Na, sodium; Ni, nickel; O, oxygen; P, phosphorus). Analysis confirms Ni and Ti as primary components, with the presence of other elements indicating surface contaminants.